The present invention relates in general to an energy dispersive X-ray analyzer, and more particularly to an energy dispersive X-ray analyzer which is capable of detecting the X-rays at high sensitivity without influencing the resolution of a system even when mounted to a high resolution scanning electron microscope having an objective lens of an inlens type or an objective lens of a magnetic field leakage type attached thereto, and also which is suitable for performing the high precision X-ray analysis.
In order to perform the high precision X-ray analysis in an energy dispersive X-ray analyzer (hereinafter referred to as "an EDX" for short, when applicable) employing an energy dispersion X-ray spectrometer, such as a silicon semiconductor detectors it is necessary to detect the X-rays which are emitted from a sample at high sensitivity and also to remove the scattering electrons (the reflected electrons) which are emitted attendantly from the sample due to the collision of the incident electron beams with the sample. Those reflected electrons become the background noises in the X-ray spectrum and also influence on the precision or the like in the quantitative analysis.
As shown in FIG. 1, in a detector included in a conventional EDX, in order to remove the scattering electrons 10 which pass, together with the X-rays 14, into an EDX device 12 as an X-ray spectrometer from a sample 7, a ring-like permanent magnet 17 is provided as an electron trap in the head portion of the EDX device 12 and the orbits of the scattering electrons 10 are curved by the magnetic field which is generated by that permanent magnet, thereby preventing the scattering electrons from entering into the EDX device.
In order to perform the high resolution observation with respect to the sample, the scanning electron microscope of a system in which the sample is arranged in the magnetic field generated by the objective lens (the inlens system or the magnetic field leakage system) is often used. However, in such a scanning electron microscope, since the sample is arranged in the magnetic field of the objective lens, if the EDX spectrometer which has the permanent magnet as the electron trap in the head portion of the X-ray spectrometer is brought close to the vicinity of the samples the magnetic field of the objective lens is disturbed by the magnetic field which is generated from the permanent magnet provided in the head portion of the X-ray spectrometers and hence the high resolution observation can not be performed. This is a problem inherent in the prior art. As a result, in such a high resolution scanning electron microscopes the EDX spectrometer can not be brought close to the sample, and hence the high sensitivity X-ray analysis and the high resolution observation can not be compatible with each other. This is another problem inherent in the prior art.